Related papers: Stringy Unification Helps See-Saw Mechanism
Despite the successes of the Standard Model of particle physics, it is known to suffer from a number of deficiencies. Several of these can be addressed within non-supersymmetric theories of grand unification based on $\mathrm{SO}(10)$.…
We study a non-supersymmetric SO(10) Grand Unification Theory with a very high energy intermediate symmetry breaking scale in which not only gauge but also Yukawa coupling unification are enforced via suitable threshold corrections and…
We discuss a minimal renormalizable Pati-Salam theory based on the $SU(4)_{\rm C}\,\times\,SU(2)_{\rm L}\,\times\,SU(2)_{\rm R}$ gauge group, with unification scale Higgs multiplets taken as $SU(2)_{\rm L}$ and $SU(2)_{\rm R}$ doublets,…
The string landscape suggests that the supersymmetry breaking scale can be high, and then the simplest low energy effective theory is the Standard Model (SM). We show that gauge coupling unification can be achieved at about 10^{16-17} GeV…
The idea of grand unification in a minimal supersymmetric SU(5)xSU(5) framework is revisited. It is shown that the unification of gauge couplings into a unique coupling constant can be achieved at a high-energy scale compatible with proton…
A simple Pati-Salam SU(4) model with a low symmetry breaking scale of about 1000 TeV is presented. The analysis concentrates on calculating radiative corrections to tree-level mass relations for third generation fermions. The tree-level…
We propose a Minimal E_6 Supersymmetric Standard Model (ME$_6$SSM) which allows Planck scale unification, provides a solution to the $\mu$ problem and predicts a new Z'. Above the conventional GUT scale $M_{GUT}\sim 10^{16}$ GeV the gauge…
The simplest interpretation of the global success of the Standard Model is that new physics decouples well above the electroweak scale. Supersymmetric extension of the Standard Model offers the possibility of light chargino and the…
In previous work, we presented a statistical scan over the soft supersymmetry breaking parameters of the minimal SUSY $B-L$ model. For specificity of calculation, unification of the gauge parameters was enforced by allowing the two…
In supersymmetric SO(10) grand unified models, we examine the lepton flavor violation process $\mu \rightarrow e\gamma$ from having the SU(2)$_R\times $U(1)$_{B-L}$ gauge symmetry broken at an intermediate scale $M_I$ below the SO(10) grand…
We explore supersymmetric Type I string-motivated three-family scenarios in which the Standard Model is embedded within two sets of intersecting D branes with U(1)-extended Pati-Salam gauge groups. We study a model inspired by the Shiu-Tye…
In warped supersymmetric grand unification, XY gauge particles appear near the TeV scale along with Kaluza-Klein towers of the standard model gauge fields. In spite of this exotic low-energy physics, MSSM gauge coupling unification is…
A model of gauge-mediated supersymmetry breaking is constructed in which the low-energy physics depends on a single dynamical scale. Strong coupling dynamics of gauge theories plays an important role, in particular through its effects on…
We embed the minimal left-right model SU(2)_L*SU(2)_R* U(1)_{B-L} into an SU(4)_W gauge group, and break the unified group via five-dimensional S^1/(Z_2*Z_2) orbifolding. Leptons are fitted into SU(4)_W multiplets and located on a symmetry…
Contrary to commonly held belief, we show that one can obtain a low value for $M_R$, the $SU(2)_R$ breaking scale, in grand unification theories based on $SO(10)$. This possibility emerges in the supersymmetric version of $SO(10)$ with a…
Conventionally for observable $n-{\bar n}$ oscillation through Pati-Salam intermediate gauge symmetry in $SO(10)$, the canonical seesaw mechanism is also constrained by $M_R \sim M_C \le 10^6$ GeV which yields light neutrino masses much…
We present a supersymmetric left-right model which predicts gauge coupling unification close to the string scale and extra vector bosons at the TeV scale. The subtleties in constructing a model which is in agreement with the measured quark…
I derive conservative upper bounds on the supersymmetry breaking parameter $m_{1/2}$ as a function of the strong coupling in the Standard Supersymmetric Model (SSM) using gauge coupling unification. I find that over more than $99\%$ of the…
Gauge unification in a five dimensional supersymmetric SO(10) model compactified on an orbifold $S^1/(Z_2 \times Z_2^{\prime})$ is studied. One orbifolding reduces N=2 supersymmetry to N=1, and the other breaks SO(10) to the Pati-Salam…
We study supersymmetry breaking by Scherk-Schwarz compactifications in type I string theory. While in the gravitational sector all mass splittings are proportional to a (large) compactification radius, supersymmetry remains unbroken for the…